1. Field of the Invention
The present invention generally relates to a patient interface for use in a pressure support system that supplies a flow of gas to the airway of a patient.
2. Description of Related Art
There are numerous situations where it is necessary or desirable to deliver a flow of breathing gas non-invasively to the airway of a patient, i.e., without intubating the patient or surgically inserting a tracheal tube in their esophagus. For example, it is known to ventilate a patient using a technique known as non-invasive ventilation. It is also known to deliver continuous positive airway pressure (CPAP) or variable airway pressure, such as a bi-level pressure that varies with the patient's respiratory cycle or an auto-titrating pressure that varies with the monitored condition of the patient. Typical pressure support therapies are provided to treat a medical disorder, such as sleep apnea syndrome, in particular, obstructive sleep apnea (OSA), Cheyne-Stokes respiration, or congestive heart failure.
Non-invasive ventilation and pressure support therapies involve the placement of a patient interface, which is typically a nasal, nasal/oral mask, or a total face mask, on the face of a patient. The patient interface couples the ventilator or pressure support system with the airway of the patient, so that a flow of breathing gas can be delivered from the flow/pressure generating device to the airway of the patient.
Because patient interfaces are typically worn for an extended period of time, a variety of concerns must be taken into consideration. For example, in providing CPAP to treat OSA, the patient normally wears the patient interface all night long while he or she sleeps. One concern in such a situation is that the patient interface is as comfortable as possible, otherwise the patient may avoid wearing the interface device, defeating the purpose of the prescribed pressure support therapy. It is also desirable for the patient interface to provide an adequate seal against the patient's face without discomfort.
Typically, patient interfaces include a member housing shell and a cushion (also referred to as a seal or seal member) attached to the shell. The cushion contacts the surface of the patient and operates to both locate and seal the interface with the face of the patient. The member is held in place by a headgear assembly that wraps around the head of the patient. Together, the patient interface and headgear form a patient interface assembly. A typical headgear assembly includes flexible, adjustable straps that extend from the patient interface to attach the patient interface to the patient.
The present invention provides improvements over prior art patient interfaces.